When it comes to sharing spoilers, Mark Ruffalo is Marvel's MVP -- Most Vocal Pest -- with Tom Holland as Rookie of the Year.

They just can't help themselves.

It's not always Ruffalo's mouth that gets him into trouble. You'll remember that it was his phone that did the deed before "Thor: Ragnarok," accidentally live streaming the start of the movie to his fans.

Last July -- before "Thor: Ragnarok" even came out -- Mark Ruffalo (Bruce Banner/The Hulk) had a "Good Morning America" interview with fellow "Avengers" star Don Cheadle (James Rhodes/War Machine). During the talk, Ruffalo decided to bring up the deaths at the end of "Avengers: Infinity War":

"Wait till you see this next one, ha -- everybody dies."

He even starting to say "half" the people died before changing it. He realized he goofed, but only Don Cheadle knew at that point how badly he goofed:

"Infinity War" does end with half the population being vaporized by Thanos, although that's not the end of the story by a long shot. That's why we have "Avengers 4" coming next year, previously called Part 2 to the Part 1 of "Infinity War."

That was last July and Ruffalo got away with his spoiler -- successfully turning it into a joke. Tom Holland was even less smooth when he casually shared a spoiler in front of a recent audience.

Holland (Peter Parker/Spider-Man) was at a screening of "Infinity War" in Hollywood. He was announced to great applause, then told the crowd, "I'm alive!" He could've passed that off as a joke, but he later asked if the audience had just seen "Infinity War" or if they were just about to see it. They were just about to see it.

Tom Holland's Peter Parker/Spider-Man turned to dust, along with half the world, at the end of "Infinity War," but since he has another "Spider-Man: Homecoming" movie coming out next year, don't worry too much about him.